The gospels say: He will baptise you with the Holy Spirit and with fire [cf. Mt 3:11]. What is Baptism with fire?
The question refers to the verses in the third chapter of the gospel according to St Matthew and the sermon of John the Baptist. In verses 11-12 John says: I indeed baptize you with water unto repentance, but He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire. His winnowing fan is in His hand, and He will thoroughly clean out His threshing floor, and gather His wheat into the barn; but He will burn up the chaff with unquenchable fire. Fire is a cleansing agent, not as material as water yet more effective; In the Old Testament fire is a symbol for the sovereign intervention of God and of his purifying Holy Spirit (cf. Isa 1:25, Zach 13:9, Mal 3:2-3, Sir 2:5).